The present invention relates to a method of and an apparatus for producing labels.
UK-A-2122968 and UK-A-2127378 each disclose a method of producing a succession of self-adhesive labels carried on a length or release backing material. A succession of pre-printed labels is adhered to a web of paper which is releasably adhered to a release backing material. The web of paper, optionally together with the pre-printed labels, is then die cut to form the resultant labels. Those methods encounter a problem due to stretching of the web of paper during the production method and/or during an earlier pre-printing process in which the web of paper is pre-printed with a succession of images. This stretching can result in the applied pre-printed labels being inaccurately positioned on the web of paper.
UK-A-2185366 discloses a computer controlled horizontal wrapping machine which produces hemetically sealed packages. EP-A-0085418 discloses a method and apparatus for applying self adhesive labels to articles to be labelled. EP-A-0019718 discloses a position control system for a moving web. US-A-4070226 discloses a registration system for bringing a plurality of moving articles into registration with each other.
The present invention aims to overcome this problem of the prior art.
Accordingly the present invention provides a method of producing a succession of self-adhesive labels carried on a length of release backing material, the method comprising the steps of:
(a) providing a laminar material which includes a release backing material as a lower layer and an upper layer comprised of a web of self-adhesive backed material or a layer of pressure-sensitive adhesive;
(b) depositing a succession of pre-printed labels onto the upper layer of the laminar material and adhering the pre-printed labels thereto, the laminar material being conveyed past a label applying station; and
(c) cutting through the upper layer of the laminar material as far as the release backing material thereby to form the required self-adhesive labels; wherein the rate of deposition of the pre-printed labels onto the upper layer is controlled by detecting the position of pre-printed labels, comparing the detected position with a desired position of the pre-printed labels and changing the said rate of deposition in response to that comparison.
The pre-printed labels may be detected either before or after they have been deposited onto the laminar material.
The present invention further provides an apparatus for producing a succession of self-adhesive labels carried on a length of release backing material, the apparatus comprising means for depositing at a label applying station a succession of pre-printed labels onto the upper surface of a laminar material, which includes a lower layer of a release backing material and an upper layer comprised of a web of self-adhesive backed material or a layer of pressure-sensitive adhesive, the pre-printed labels being adhered to the laminar material, means for conveying the laminar material past the label applying station, a cutting device for cutting through the upper layer of the laminar material as far as the release backing material thereby to form the required self-adhesive labels, means for detecting the position of pre-printed labels, means for comparing the detected position with a desired position of the pre-printed labels, means for controlling the said depositing means in response to the means for comparing thereby to change the rate of deposition of the pre-printed labels onto the upper layer.
The detecting means may be located either upstream or downstream of the label applying station, with the detecting means being arranged to detect the position of pre-printed labels either before or after, respectively, those labels have been deposited onto the laminar material.